Machine for rough milling and generative finishing of machine elements



June 3, 1952 E. w. MILLER MACHINE FOR ROUGH MILLING AND 2,599,408 GENERATIVE FINISHING OF MACHINE ELEMENTS 7 Sheets-Sheet 1 Filed June 6, 1946 LvsL ESE June 3, 1952 E. w. MILLER 2,599,408

MACHINE FOR ROUGH MILLING AND GENERATIVE FINISHING OF MACHINE ELEMENTS Filed June 6, 1946 7 Sheets-Sheet 2 June 3, 1952 E w, MILLER 2,599,408

MACHINE FOR ROUGH MILLING AND GENERATIVE FINISHING OF MACHINE ELEMENTS Filed June 6, 946 7 Sheets-Sheet I5 June 3, 1952 E. w. MILLER MACHINE FOR ROUGH MILLING AND GENERATIVE FINISHING OF MACHINE ELEMENTS 7 Sheets-Sheet 4 Filed June 6, 1946 June 1952 E. w. MILLER MACHINE FOR ROUGH MILLING AND GENERATIVE FINISHING OFaMACHINE ELEMENTS '7 Sheets-Sheet 5 Filed June 6, 1946 7 Sheets-Sheet 6 E. W. MILLER MACHINE FOR ROUGH MILLING AND GENERATIVE FINISHING OF MACHINE ELEMENTS June 3, 1952 Filed June 6, 1946 June 3, 1952 E. w. MILLER 2,599,408 MACHINE FOR ROUGH MILLING AND GENERATIVE FINISHING OF MACHINE ELEMENTS '7 Sheets-Sheet 7 Filed June 6. 1946 Patented June 3, 1952 MACHINE FOR RGUGH MILLING AND GEN- ERATIVE FINISHING OF MACHINE ELE- MENTS Edward W. Miller, Springfield, Vt, assignor to The Fellows Gear ShaperCompanm-Springfield,-'Vt., a corporation of Vermont Application June 6,, 1946, Serial N 0. 674,838

10. Claims. (Cl. 90-'-3) This invention "relates to the art -of metal Working by cutting tools. Its primarybbject is to' efiect rough cutting and finish cutting of a work pi-ece'by means of separatecu-tters in a progressive operation without changing the-manner in-which the work piece and tools aresetup in the-machine; A part of the object is toimpart a relative generatingmovement between the work and the cutter-by which the finishing cut is made of-such a character that-the surfaces generated on the work are otherwise than-- complemental to the profile of the cutter.- A final objects-is to pro duce finished work pieces from-a-previously'uncut blank in lesstime than is requiredby' the procedures' heretofore used, and with an accuracy and quality of finish equal to-that obtained by the :moretime consuming roughing and finishing operations of the priorart.

The principlesof the invention may be applied in mac'hinetools 'of various designs-for producing machin'e'ele'ments and other work pieces of various kinds.- One type of work which I have had particularlyin'view-is for the rough cutting and generative finish cutti-ng'of gear teeth.- Theembodi ment of theinvention-hereillustrated =iS'fa machinedesigned for cutting gearswi-th generated tooth face curves bythe-agency of milling eutters and in the following description those'principles are explained with reference-to-that machine; but without intent to limit-theseope of the invention specificallythereto.

In the drawings,

Fig. 1 is a front elevation of the machine reierredto;

Fig- 2 is avertical section of themachine taken on line 2-2 of'Fig. 1

Figs. 3 and 4 are detail sectionstakenoniines 34-3 and 4-4; respectively of-Fig-.-2

Figs-7 is a partial rear elevationof themachine andJa' partial-section showing details ef-the work indexing mean-swith which *the'machine'is pro-- vided; v

Fig-c =9 is a L fragmentary-rear'elevation -of- -'-the machineshowing the means by which generative rotation is 1 irnp'aidzedto the work-during the-finish *cu'tting action of the machine; 4

FigSQIO- and 11 are sectional views taken on lines fll -l B and H-l l respectively,- =01- -Fig'-. 9

Fig 1-2 is a diagramcf the hydrauliesystemby which cer-tain parts of themachinecare impelled in carrying out-their-operations;

:13 is-.a schematic diagram of the-electrical means bywhich other parts are driven and all parts are controlled.

Like reference characters designate the same parts wherever they occur in all the figures.

In this machine two milling cutters, shownat R and F,-are mounted on thesame shaft. The cutter R is-the; roughing cutter and may have a profile similar to that of the spaces between the gear teeth. That is, it may be whatis commonly known :as a formed cutter; although that is not an essential factor. It is rotated for cutting and given a reciprocating translative movement across the circumference of a work piece W in the direction of the axis of the work piece while the latter-is withheld from rotation, and is fed toward the axis of thework piece'between reciprocations. The cutter F is a finishing cutter, which is rotated and reciprocated in thesame manner as the roughing cutter in the tooth spaces cut by thelatter, while the work piece is rolled back and forthacross its intruding rim to cause generation of--face-curves on the work piecewhich are conjugate to the profile of the-cutter.

The structural features of the machine comprise a base 10 having separated uprights II and IZ'between which is located a stool I3 on which a cutter carriage l 4- is supported to reciprocate on-guideways 15 and I6, and the'cutter spindle fl- -is rotatably mounted in suitable .bearings in the carriage--l'4.--

A work carriage I8 is mounted on the base uprights H and 12 so as to bridge-acrossthe-intermediate space in which the cutters are located.- Thi carriage is movable reciprocably in a horizontal path on guideways on the uprights and has a rotatable work spindle l9 (Fig. 2) and atail stock 20 supporting a retractable dead center 21, in-positionto cooperate with the work spindle l 9 tosupport work pieces.

The stool I3 is connected with a cylindrical tubular column -22--contained in a sleeve bearing 23-inthe base, as-shown by Fig. '2. Secured to the interiorof the column 22 and bearingagainst the underside of a shoulder 24 therein is an-annular nut 25-, which meshes with a tubular screw t-fi suppor-ted :on a step bearing 21 in the base and centered by an annular bearing 28. Progressivesteps-of feeding movement of the cutters toward the workare imparted to the stoolautomati'cal-ly b'y 'a'ratchet 29-and pawl 30 (Fig. 3). This ratchet secured to a shaft- 3| which carries-a bevel-gear '32 meshing with a bevel-gear 33 on an upright shaft '34. Thelattershaft transmits rotation through'a bevel gear pair 35 to a horizontal shaft 36 on which a pinion 31 is se-' cured. This pinion drives a face gear 38 through an idle pinion 39. The face gear 38 is secured to the base of tubular screw 26 so that it rotates the screw whenever the shaft 3| i rotated, thereby raising or lowering the stool and cutters according to the direction of rotation of the shaft. Rotation of the stool while being raised and lowered is prevented by guides 39I on the base uprights contained in guideways in a band 392 which surrounds the rim of the stool and is clamped thereon. Stops 393 on the guides limit rise of the stool.

The direction of rotation imparted by the ratchet 29 is that which causes the stool to be raised. Pawl 38 is carried by an endwise movable bar 40, the upper end of which is reciprocable in a guideway 4| in the base, and the lower end of" which is connected to the core 42 of a solenoid 43 secured immovably to the base. A spring 44 normally holds the pawl carrier in the elevated position shown in Fig. 3, where the toe of the pawl is separated from the ratchet by a shield 45. A spring 46 is arranged to bear on the pawl and carry its toe into engagement with the nearest tooth of the ratchet when downward movement of the pawl carrier brings the pawl clear of shield 45. A long enough movement is given to the pawl carrier in each actuation to turn the ratchet by at least one tooth pitch. The solenoid is energized at intervals by means later described and so imparts a. step by step movement to the stool The stool is rapidly withdrawn from the work after completion of a series of cuts, to permit indexing of the work during the rough-cutting procedure, and returned to position for commencing a further series of cuts after indexing, by a reversible electric torque motor 41, which is coupled by a chain 48 with a sprocket 49 also secured to shaft 3|. The motor 41 is started, stopped, reversed and restarted automatically at prescribed intervals. When it is activated, the pawl driving solenoid 43 is deenergized and the pawl then is held clear of the ratchet.

The drive for the cutter shaft I1 is taken from an electric motor 50 (shown only in the electrical diagram), which drives a shaft 5| (Fig. 1) by a belt and a pulley 52. Shaft 5| is geared by a spur gear pair 53 to a shaft 54, which drives through bevel gears 55 and 56 a shaft 5'! contained in a bearing 58 secured in the bearing 28, previously described, coaxially therewith and with the bearing sleeve 23.

Shaft 51 is made fast by splines 59 and a pin 60 to a tubular shaft section BI which has a sliding splined connection with a shaft 62 mounted rotatably in a bearing 63 secured to the column 22 of the stool; shaft 62 having shoulders embracing bearing 63 so that it is moved endwise whenever the stool is moved, and to the same extent. Shaft 62 is connected by a bevel gear pair 64 with a shaft 65 mounted in a radial bearing in the stool, from the outer end of which the shaft protrudes, and the outer end of shaft 65 is connected by a belt and pulley, or chain and sprocket, drive 66, 61, 68 (Fig. 5), with a shaft 59. Shaft 69 is contained in a bearing 10 supported by a bridge structure II which is mounted on the stool and overlies a part of the cutter carriage I4. A worm shaft I2 is mounted rotatably in a housing 13 on said bridge structure in alinement with shaft =69, to which it is coupled by a coupling 14. A worm I5 on this worm shaft meshes with a worm wheel 16 secured to the cutter spindle IT.

The alined shafts B9 and 12 are parallel with the guideways on which the cutter carriage I4 reciprocates, and the worm housing 13 has a slidable engagement with the carriage, whereby driving connection is maintained with the cutter spindle throughout the full range of reciprocation of the carriage; and the worm wheel I6 is equal in diameter, or approximately so, at its pitch circle to the cutters R and F, the shaft bearings being suitably located to permit this condition to exist. Thus the cutting speed of the cutters relative to the work is maintained constant during reciprocations in both directions, provided the speed of the worm is constant.

Reciprocating motion is imparted to the cutter carriage by hydraulically actuated plungers 11 and I8 working in cylinders 19 and 80, respectively, secured on the stool. These plungers bear against oppositely facing abutment shoulders 8| and 82 on the carriage, whereby working fluid admitted alternately to the cylinders, and correspondingly relieved from them, causes the carriage to be moved back and forth. Connections for admission and exhaust of the working fluid are indicated at 83 and 84 in Fig. 6.

The work carriage I8 is reciprocated by means of a piston 85 (Fig. 1) working in a hydraulic cylinder 86. The cylinder is fixed rigidly to the upright I2 of the base structure in parallel with the carriage guideways, and the piston is formed as a collar or flange surrounding a rod 81, which extends through both heads of the cylinder and is secured to the carriage by a bracket 88. The head 89 at the left hand end of the cylinder as viewed from the front (Fig. 1) serves as a stop to limit the movement of the carriage to the left and locate the carriage in the position for performance of the rough cutting operation. In that position the axis of the work spindle is directly over the roughing cutter R and the path in which that cutter reciprocates. Admission and exhaust of working fluid to the cylinder at opposite sides of the piston is controlled by means later described in connection with the hydraulic diagram. However, a part of such means is shown in Fig. 1 consisting of adjustable dogs 90 and 9| on the carriage I8 adapted to move a trip valve back and forth.

A hydraulic indexing motor 92 (Fig. 2) is connected with the work spindle I9. This motor may be of any one of several known types of rotary motor and includes a housing or stator which is secured to the carriage structure and a rotor secured to the spindle. Pressure fluid is admitted to this motor under control of valve means, later described, from time to time when indexing of the work is needed.

In the operation of this machine the carriage remains stationary while rough cutting of the work is being performed by the cutter R, and the work is indexed after each tooth space or groove has been cut to the prescribed depth, until all of the prescribed number of tooth spaces or grooves have been out. Then the carriage is shifted (to the right with respect to Fig. 1) into a position permitting the finishing cutter F to act on the work, and is reciprocated, with simultaneous rotary movement of the work spindle, so that the side of the work piece next to the cutter is rolled across the rim of the cutter to cause generation of surfaces divergent from the profile of the cutter. The rotative or angular component of movement is imparted to the work by the conjoint action of a cam member 93, which I have called a former, and abutthe extremity of dog I38 will engage cam surface I36 and displace the coupling pawl when the arm I nears the end of its oscillative motion in one direction during the generating phase of the operation of the machine. The bracket has in addition a cam surface I4I in position to be engaged by a shoulder I42 on arm I00 at the same time when the coupling pawl I02 has been displaced, or immediately before. Shoulder I42, acting on cam surface I4I, shifts the arm I23 with consequent actuation of valve I22 to admit working fluid to the indexing motor, whereby the work is indexed during separation of pawl I02 from the index plate. The tail of the pawl passes the extremity of the dog I38 directly after the indexing motor has been thus started, whereby the pawl is free to reengage another notch of the index plate, being actuated thereto by a spring, not shown. On the return movement of arm I00 thereafter, the tail extremity of pawl I02 displaces the dog I38 in passing, without being itself displaced; the spring pressed pin I40 then yielding to permit such displacement of the dog.

The hydraulic system by which the cutter can'iage, work carriage, indexing motor and former impelling motor of the machine embodiment here described are operated is shownin Fig. 12. Three pumps designated I43, I44 and I45 are connected to be driven simultaneously by an electric motor I46 (Fig. 13). All the pumps take working fluid, which may be oil, from a source of supply, such as a tank, indicated by the line I41. Pump I43 delivers oil to a valve I48 from which there is a return or bypass connection I49 to the source and a delivery connection having branches I50, I5I leading to a trip or pilot valve I52 and a reversing valve I53, respectively. Valve I48 is also connected by a line I54 to a control valve I55 operated by a solenoid I56. When the solenoid is energized, valve I55 closes a connection between the line I 54 and a return line I5,6a,;- whereby back pressure is developed in line I54 which hold closed the by-pass connection I49 from the valve I48 and causes oil to be delivered under pressure to lines I50 and I5I. But when the solenoid I56 is deenergized, it shifts valve I55, or allows it to be shifted by a spring, so as to release the back pressure in line I54 to the ports connected with the lines 83 and 84, re-

spectively, which conduct oil to the cylinders 19 and 80 (shown in Fig. 6), of the means for reciprocating the cutter carriage. The slide element in valve I53 is shifted back and forth by pressure delivered through pipes I51 and I58 under the control of pilot valve I52. The pilot valve contains an internal rotary valve member which is turned alternately in opposite directions by adjustable dogs I60 and I6I on the carriage I 4. In one position of the pilot valve, pressure is transmitted through the connection I51 to the left hand end of valve I53, thereby putting that valve in position to transmit pressure fluid from the line I5I through line 83 to cylinder 19, and to connect the line 84 from cylinder 80 with the exhaust connection I62 from valve I53 to the oil source. In the other position of the pilot valve, these connections are reversed. A pipe line I63 leads from the pilot valve to the supply tank, for permitting release of oil from either connection I51 or I58 when 8 the other is connected to receive pressure from the pump.

Pump I44 is similarly connected through a bypass control valve I64 with a bypass to the oil tank and pressure with lines I65 and I66 leading, respectively, to a slide valve I61, which controls the former-impelling motor 91, and to the control valve I22 for the indexing motor 92. Slide valve I61 is similar to the valve I53. In one position it connects the pressure line I65 with a line I68 leading to motor 91 for driving the latter in one direction, connecting a line I69 from the opposite side of the motor with an exhaust connection I10; and in the opposite position, the slide valve connects the pressure line I65 with line I69 for driving the motor in the opposite direction, connecting line I68 with the exhaust connection I10. Pressure is admitted to opposite ends of the reversing valve I61 to shift the slide element therein by pipe lines In and I12 under control of the valves which control, and are controlled by, the work carriage I8, so that the direction of force application on the former 93 is reversed with reversals of the force application to the work carriage motor.

The pressure line I66 from the pump I44 is connected by a branch connection with a control valve I13 having an internal slide member which is coupled with the core of a solenoid I14, and a pipe line I34 leads from the casing of valve I13 to the plunger I32 by which the tripping dog I3I of the pawl I02 is actuated. In the deenergized condition of solenoid I 14, line I34 is in exhausting connection with the oil supply; and when the solenoid is energized, pressure is applied to plunger I32.

Working fluid for driving the indexing motor 92 is delivered from valve I22 through a pipe line I16. A branch I11 from this line passes to a port in a slide valve casing I18, from another port of which a line I19 leads to the pressure chamber in which plunger I39 is mounted. An-

other branch from line I16, containing a retard-- ing coil I leads to one end of the valve casing I18 for shifting the slide valve element I 8I therein endwise toward the other end 01' the casing, from which there is an exhaust connection I82. A return bypass, controlled by a check valve IBM is connected across the retarding coil.

With the valves I22 and IN in the positions shown in Fig. 12, which are those occupied when solenoid I21 is inactive, the line I16 and its branches are cut oil from the pressure line I66. When the solenoid I 21 is energized. and also when arm I23 is displaced by action of the arm I09 which oscillates the work spindle, line I16 is connected with the pressure line I66. Also pressure exerted with delayed action through coil I80 shifts slide valve I8I and causes pressure to be exerted on plunger I39, thereby shifting dog I38 into the path in which the tail of the index pawl I02 travels.

Pump I45 delivers pressure through branches I84 and I85 of a pipe line to a reversing valve I86 and a pilot valve I81. The pilot valve I81 has fingers actuated by the dogs and 9I on the work carriage to'connect the pressure line I85 alternately with a pipe line I88 leading to one end of the reversing valve I86, and a pipe line I89 leading to a control valve I90 which is actuated by a solenoid 'I9I. A pipe line I92 leads from the control valve I90 to the end of reversing valve I86 opposite to that with which the line I88 is connected. Pipe lines I93 and I94 dead to the oppositeends of the" motor: cylinder 86 by which the work i carriageeisr rec'ipro'cated, and are connected alternately with thei pressure =1in'e I 84 and an exhau'st :line: :I 95; :fIhe lines I1 I :7 and I12 leading to opposite ends of the'reversing -va;lve I 61 are l'coupled' awith the: lines I 93 and 194, respectively,- whereby :the -motor 91 (by which former 93 is impelledi is reversed: simultaneou'sly -with .the" worlc carriage I B.

' When 'solenoid' ISIfisinact-ive, valve I99 closes the connection i between: thezilines I89 2 and t I 92,

z and connectssline I 92 :iwithrthe :exhaust r 'line,

permitting thefreversing valve I86 :to I occupy the-:pos'iti'on wherein lines I84? andv 'I 94' are: connected and pressure is: applied 'torthe work carri'age motor to' holdithef'carriage 'in; .thevposition 1 shown in liig. J 1 and: force" is exerted-on the former iimpelling motor,- 91' to causexthe'x former -t be.pressed against abutment 94" and the head 99a on connecting rod 99-i-to1-be pressed against 3 'Iheiimotorsi I and :solen'oids "mentioned. in; the

. preceding description ares-controlled electrical- Y :ly 'by"switches, coils,r;contactors and timing relays :i'shown' in :the electrical wiring 'ildi'agram, Fig: 13.

A starting iswitch" skandtstopvswitch" s are in "circuit i'with Xthewcoilfof raamagnetic; starter A "which," :when iaenergized, rcloses ithe starter confacts and appliesupowerf-to? the: pumpi motor I 46 by which the pumpsilltt Mloand- I45 are driven. Another-.="starting switch s '1 and 'stop switch s are in circuit with the coil of magnetic starter A which, when energizedgrclosessxacontact c This i :in *turn *energizesfiither-coil' of "magnetic starter B "for the. cutter motor=-59','-which "closes the starter and applies power: to that motor.

Another: starting switch s -andrstop switch s "are intcircuitwith the coillB '.which, Iwhen -en- 'ergized; closes a contact c :and energizes coil I56 whi'choperatesihydraulicf'valve 155. The

solenoids I 2 U and I 2 1 are energized; placing stop pin- I I1 in :blocking-ztposi-tiong and causing hy- "dra'ulic. pressure"v to be -applied to" :the indexing motor 92; P'ressure is; also? applied ton the hy- "draulic motor 91, causing-{former -93. to be pres'sediagainst abutment 94 andwheadri99cr to be pressed against stop pm" I I1. Thus when the switches s stand 8 (which Y3 Let itbe assumed thalfi-thei'stbol iiSfdOWIl aand switches s s and s have been closed. -Ea'ch time the" cutter -icarriage 1 I 4 reaches the "endof its "strokein -one direction, it .010888 the interclock 0 which energizese-the f'coil of contactor D- through? noseawontmt c f and one "of the-closed contacts of contactor' D The contact 0 of contactor-"D closes andenerg-izes coil of solenoid 43 1 which 1 actuates the feedpawl 30,- and lifts the stool 1 through" a step bfzieeding movement.

This continues until the stool reaches the predetermined upper limit of its travel. Atlthis time, limit switch 1 closes. lt isso-closedby an actuator I91 (Fig. 1) =nrcninted. ald-jiistalolyon the stool to enable I the location of'the upper :limit oft'move'ment to be varied. closingrof switch Z energizes coil of'rcontac'torf D "which operates a contact c 'to close the motor circuit of timing relay iD ..'I'heitimerxD -zoperates.

After a time. (allowing the cutterwcarriagee to take a complete stroke) 3 the-timer -contact= -c closes,' whichenergiz'es coil of contactor-i93 indexing motor '92. pawl is tripped (disengaged .f-rom -ind'e'x plated 03 and quickly" released) ,t'the' work spindle indexes through normally closedllcontact'" 0 A contact c of D 'thGnICIOSES :thBfCOiB circuit rof the "stool motor starter D .whi'clrbecomes-=active=aand applies power to stool motor '41'=to-lower the stool.

Another contact 'c f of contactor D ,:causes the ratchet coil E of a counter I98 (see Fig. 1 ):e-to be energized. causing 'thetc'o'unter to 'couiitfone.

' Limit switch 'l cis iope'necl when the i stool r-commences its 'descent and: switch Z is .closedv'when the stool reaches its bottom position. .This2:c1ospermit indexing of the work; 'I'heI'C0i1L6f'Z'SO1e- "noid' I21 being then energized, the valvez I22-iis open admitting fluid: pressureitd the hydraulic .Hence,': when ithe index 0 was closed,which energized coil of contactor This operation of contactor throws "r'bhe control' baclg to the interlock: 0 on ithei'cutter carriage so that at 'theendof each'strokei ofathe cutter carriage, the interlock circloses rand causes the stool" operating ratchet 29 '-'to"' be turned-up one notch. "Asithe':stool reachesrthe 'from plunger I39 of'dog I38.

arm I09.

top limit "(controlled by Z thev stool is 'lowered as before,

The counter I98 is turned 'byits"ratchet-;one step each time the stool is raised.

After the counter I 98:has counted the "number of notches inwork (for whichfit is set)-.:-the

energized. A contact '0 of- G energizest-coil of contactor G The last namedxcontactor closes its contact 0 inthe. circuit of :the valve operating solenoid I 9 I. and-"opens its; normally closed. contact 0 in the circuit of solenoidtl21 and the pin operating solenoid .I 20, wherebythe means for reciprocating the "Work slide areaiset into operation. and the'obstruc'ting pin 'II1- is moved out of the "way of" the' oscillating --work spindle arm. 'Soleno'id I21 is"deenergized,'-releasing oil pressure from index-motor92mand Controlof valve I22 is thereby transferred "to: the arm I23, which is free tobe controlled by the :oscillating: spindle When; arm I09 is rotated-counterclockwise to nearthe end of itsstroke; the-indexing operation can take place. Contactor coil G is deenergizedafter counter'l98 hasvbeen reset and coil of G has energized.

Coil of G contactoris thendeenergized.

This closesthecircuit of a coilG, which .by

. closing a:. switch in one of thecircuits of motor 11 Ill, causes the motor to shift the abutmentcarrying block I06 into its position for performing the finishing operation on'the work, as determined by the adjustable stop IIO. When in that position an interlocking'swit'ch Z is engaged by the-block and closed,whereby the coil of a contactor H is energized and three contacts are closed. The stool is raised to the elevated position suitable for finish cutting by its motor 41 and held there until all the teeth of the work piecehave been finished. This elevated position is determined by the stops 393. A coil'E in the counter is operated to release the driving ratchet thereof and permit the counter to return to zero.

Following actuation of solenoid I9I', the work carriage is set into automatic reversal by the hydraulic system described and the impelling motor 91 for the former is reversed in time with reversals of the carriage. Thereby the work is rolled across the rim of the finishing cutter F; and it is indexed at the end of each travel of the carriage in one direction, by the indexing motor 92 when pawl I02 is tripped by dog, I38. A switch actuator I89 is mounted adjustably on the carriage in position to engage a projecting part on aswitch e which is in the circuit of the'coil E by which the driving mechanism for counter I98 is operated, and closes that switch in the course of each travel of the carriage from left to right. Closing of that switch causes the coil E of the counter to be energized and the counter indicator to be advanced a step. At the completion of a prescribed number of steps, the counter causes contact m to be closed whereby coil of contactor G is energized.

Circuits are thereby closed which cause the motor 41 to lower stool I3. The stool reaches bottom and switch Z closes, which operates contactor B. A contact of B closes the circuit of contactor coil B whereby the reversing switch of motor III is closed. The motor is driven in reverse, whereby the abutment carrying block I06 is withdrawn to the position for the first cutting operation. A short time later the coil of contactor A is deenergized, and solenoids I55, I14, I9I, I20 and I2! are deenergized, whereby the machine is stopped with the work carriage in the left hand position (Fig. 1) ready to repeat the cycle when a blank work piece has been substituted for the finished piece. The stool is lowered until it reaches a positive stop at the bottom. As its motor 41 is a' torque motor it can remain energized without harm when stalled by arrest of the stool.

It has been previously stated that the principles of the invention may be embodied in mechanical constructions of difierent designs than that here shown. Among the variations which may be made is to substitute a grinding wheel for a milling cutter as the finishing tool. However, the roughing cutter must of practical necessity be a milling cutter in order to accomplish the desired result of rapid production. Other electrical units and combinations than those here shown may be employed, within the skill of the electrical engineer; and I may employ'wholly mechanical operating and controlling means, although the hydraulic and electrical means are preferred. It is preferable also to employ electric torque motors as the means for imparting the rapid movements to the stool and the abutment carrier, as these motors are able to exert constant force when energized, even though stationary; and like motors may be used 12 instead of hydraulic motors for indexing the work spindle and impelling the former.

I claim:

1. A roughing and finishing machine tool comprisinga work carriage, a work spindle rotatably mounted on said carriage, a tool holder, roughing and finishing cutters supported by, said holder with a space between them, means for actuating said cutters, said work carriage and cutter holder being relatively displaceable to bring the roughing -cutter and'finishing cutter separately into operating'relation with a work piece mounted on the work spindle, and control means organized to hold the work carriage and spindle stationary'while the roughing cutter is in 'operatingrelation to the work piece, andto impart reciprocative. movements. to the carriage and correlated rotational movements to the spindle when the finishing cutter is in the operating relation to the work piece.

2. A'roughing and finishing machine comprising a cutter holder, a'preliminary cutter and a finishing cutter rotatably mounted on said holder with a space between them wide enough to permit each to have an operating relationship with the same work piece independently of the other, work holding means including a rotatable spindle adapted to hold a blank work piece, said cutter holder and work holder being relatively shiftable to eifect operating relationship between each cutter in turn and such work piece, means for effecting a progressive feeding displacement between the cutter holder and work holder when the preliminary cutter is in the operating relationship to the work, and means for effecting relative rolling movements between the work holder and finishing cutter when the latter is in the operating relationship to the work.

3. A roughing and finishing machine comprising a cutter supporting stool, a cutter carriage movable reciprocably on said stool, a cutter spindle rotatably mounted on the cutter carriage with its axis transverse to th directions of movement of said carriage, roughing and finishing cutters secured to said spindle and spaced apart axially of the spindle, means for imparting movement to the stool in the direction transverse to both the path of said carriage and th axis of said shaft, a work carriage movable in a path transverse to the planes of rotation of the cutters, a work spindle rotatably mounted on the work carriage with its axis transverse to the cutter spindle axis and in relation to th cutters such that a work piece secured to it can be placed, by displacement of the work carriage, into position for being acted on by either cutter independently of the other, control means for holding the work carriage and spindle stationary while the work is in operating position with respect to the roughing cutter, and means for causing the work carriage to be reciprocated and the work spindle to be rotated in correlation to eifect a rolling movement of the work piece across the plane of the finishing cutter.

4. A machine according to claim 3, combined with indexing means for the work spindle and controlling devices thereof operative to impart steps of rotation to the spindle while the work carriage is stationary with respect to the roughing cutter and also while the work carriage is in reciprocating motion with respect to the finishing cutter.

5. A roughing and finishing machine comprising a cutter supporting stool having reciprocative feeding and return movements, a cutter carriage reciprocabl on said stool in a path transverse to the directions of the movements of the stool, a cutter spindle mounted rotatably on said carriage with its axis transverse to both the path of the carriage and the directions in which the stool is movable, roughing and finishing cutters mounted on said spindle with an axial spacing between them, means for supporting a work piece in difierent locations, one of which locations is contiguous to the roughing cutter and clear of the finishing cutter and the other location is contiguous to the finishing cutter and clear of the roughing cutter, means for imparting simultaneous movements of rotation to the cutter spindle, reciprocations to the cutter carriage, and advance to the stool while the work is in position to be acted on by the roughing cutter, means for Withdrawing the stool while the work is in that position, means for indexing the work while the stool and cutter are withdrawn, control means for causing the said movements of the stool and work piece to be repeated a prescribed number of times, and means for subsequently imparting to the work piece a succession of rolling movements back and forth in cutting relation to the finishing tool, and for indexing the work piece between successive rolling movements.

6. In a machine tool having a cutter supporting stool and a cutter carriage mounted to reciprocate on said stool, means for reciprocating said carriage, means operated by the carriage to cause steps of advancing movement to be imparted to the stool, and means operated by the stool when arriving at a prescribed point in its advancing movement for causing the stool to be retracted.

7. In a roughing and finishing machine having a reciprocable work carriage, a work spindle rotatably mounted on said carriage, means for reciprocating the carriage and a former cooperating with abutments and connected with the spindle to impart angular movements to the spindle correlated with linear movements of the carriage, means for holding the carriage in one operative location and blocking the former and abutments to prevent spindle rotation, and control means for causing the carriage to be put into reciprocating movement and the former and abutments to be simultaneously unblocked.

8. In a roughing and finishing machine having a reciprocable work carriage, a rotatabl work spindle on the carriage, means for reciprocating the carriage and simultaneously turning the spindle back and forth in time with movements of the carriage, and indexing means operable under control for turning the spindle in one direction independently of said spindle turning means; control means including devices for holding the carriage at one limit of its movement and simultaneously blocking the spindle turning means, devices for causing operation of the spindle indexing means while in blocked condition, devices for unblocking the spindle turning means and putting such means and the carriage operating means into action, and other devices for causing the indexing means to act on the spindle at prescribed intervals during repeated translative and oscillative movements of the carriage and spindle, respectively.

9. In a machine of the character described, the combination of a supporting structure, a work carriage mounted to reciprocate thereon, a work spindle on the carriage, a former operatively connected with said spindle to control angular movements thereof, an abutment holder mounted on the supporting structure, abutments on said holder engaged with the former, and means for shifting the abutment holder into different positions, in one of which the former is made inoperative for causing angular movements of the spindle, and in the other of which the former is made operative for that purpose.

10. In a machin of the character described, the combination of a supporting structure, a work carriage mounted to reciprocate thereon, a work spindle on the carriage, a former operatively connected with said spindle to control angular movements thereof, an abutment holder mounted on the supporting structure, abutments on said holder engaged with the former, means for shifting the abutment holder into positions for making the former operative and inoperative, respectively, for causing angular movements of the spindle, blocking means for the former movable into and out of a position in which it prevents angular movement of the former, and common control means for said blocking means and abutment holder.

EDWARD W. MILLER,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,283,693 Derr Nov. 5, 1918 1,341,034 Beede May 25, 1920 1,983,019 DeLeeuw Dec. 4, 1934 2,136,266 Reinecker Nov. 6, 1938 2,347,997 Drummond May 2, 1944 2,387,166 Miller Oct. 16, 1945 2,394,757 Drummond Feb. 12, 1946 2,416,749 Grey Mar. 4, 1947 2,435,405 Praeg Feb. 3, 1948 

